113 lines
3.2 KiB
Python
113 lines
3.2 KiB
Python
"""
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Base classes for command pattern implementation.
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"""
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from abc import ABC, abstractmethod
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from typing import Any, Dict, List, Optional, TypeVar, Generic, Union
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# Type variable for the result of a command
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T = TypeVar('T')
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class Command(ABC):
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"""
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Base abstract class for all commands.
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Commands encapsulate business logic and ensure data integrity.
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"""
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@abstractmethod
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def execute(self) -> Any:
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"""
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Execute the command and return the result.
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Must be implemented by all command subclasses.
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Returns:
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Any: The result of the command execution.
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"""
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pass
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def validate(self) -> Dict[str, Any]:
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"""
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Validate command data before execution.
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Should be overridden by command subclasses.
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Returns:
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Dict[str, Any]: Validation result with 'is_valid' and optional 'errors'.
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"""
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return {'is_valid': True, 'errors': None}
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class CommandResult(Generic[T]):
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"""
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Represents the result of a command execution.
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Attributes:
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success (bool): Whether the command was successful.
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data (Optional[T]): The result data, if successful.
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errors (Optional[List[str]]): List of errors, if unsuccessful.
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message (Optional[str]): An optional message about the operation.
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"""
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def __init__(
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self,
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success: bool = True,
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data: Optional[T] = None,
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errors: Optional[List[str]] = None,
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message: Optional[str] = None
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):
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"""
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Initialize a new CommandResult.
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Args:
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success: Whether the command was successful.
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data: The result data, if successful.
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errors: List of errors, if unsuccessful.
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message: An optional message about the operation.
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"""
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self.success = success
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self.data = data
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self.errors = errors or []
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self.message = message
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def to_dict(self) -> Dict[str, Any]:
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"""
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Convert the command result to a dictionary.
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Returns:
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Dict[str, Any]: The command result as a dictionary.
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"""
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return {
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'success': self.success,
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'data': self.data,
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'errors': self.errors,
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'message': self.message
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}
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@classmethod
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def success_result(cls, data: T = None, message: Optional[str] = None) -> 'CommandResult[T]':
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"""
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Create a successful command result.
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Args:
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data: The result data.
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message: An optional success message.
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Returns:
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CommandResult[T]: A successful command result.
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"""
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return cls(True, data, None, message)
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@classmethod
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def failure_result(cls, errors: Union[str, List[str]], message: Optional[str] = None) -> 'CommandResult[T]':
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"""
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Create a failed command result.
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Args:
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errors: Error or list of errors.
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message: An optional failure message.
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Returns:
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CommandResult[T]: A failed command result.
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"""
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if isinstance(errors, str):
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errors = [errors]
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return cls(False, None, errors, message) |